Normal term infants will be studied to determine whether consumption of a carnitine-free diet is associated with evidence of impaired ability to oxidize long-chain fatty acids. One group will be fed a soy protein-based, carnitine-free formula and the other group will be fed a similar formula fortified with carnitine. Infants will be enrolled at 8 days of age and studied until 112 days of age. At ages 56 and 112 days, the following indices of carnitine nutritional status will be determined: respiratory quotient, plasma carnitine, beta-hydroxybutyrate, free fatty acid and triglyceride concentration, urinary excretion of carnitine and medium-chain dicartoxylic acids, and anthropometric parameters. Vegetarian (strict and lacto-ovo) children and adults will be studied to determine whether there is a dietary requirement for carnitine. Individuals consuming mixed diets will be included as controls. Plasma carnitine concentrations and urinary excretion of carnitine and medium-chain dicazboxylic acids will be determined as indices of carnitine nutritional status.